feat: add support for self-hosted draw.io via DRAWIO_BASE_URL environment variable (#163)

## Summary
Add support for self-hosted draw.io instances via build-time configuration.

## Problem
In some corporate environments, `embed.diagrams.net` is blocked by network policies. 
Users cannot use the application without access to the default draw.io embed URL.

## Solution
- Add `NEXT_PUBLIC_DRAWIO_BASE_URL` environment variable support
- Pass the `baseUrl` prop to the `DrawIoEmbed` component
- Configure Dockerfile to accept build-time argument for the draw.io URL

## Usage
```yaml
# docker-compose.yaml
services:
  drawio:
    image: jgraph/drawio:latest
    ports:
      - "8080:8080"
  
  next-ai-draw-io:
    build:
      context: .
      args:
        - NEXT_PUBLIC_DRAWIO_BASE_URL=http://drawio:8080
```

Or build directly:
```bash
docker build --build-arg NEXT_PUBLIC_DRAWIO_BASE_URL=http://localhost:8080 -t next-ai-draw-io .
```

**Note:** This is a build-time configuration. To change the draw.io URL, you need to rebuild the Docker image.

Dockerfile

@@ -22,6 +22,10 @@ COPY . .
 # Disable Next.js telemetry during build
 ENV NEXT_TELEMETRY_DISABLED=1
 
+# Build-time argument for self-hosted draw.io URL
+ARG NEXT_PUBLIC_DRAWIO_BASE_URL=https://embed.diagrams.net
+ENV NEXT_PUBLIC_DRAWIO_BASE_URL=${NEXT_PUBLIC_DRAWIO_BASE_URL}
+
 # Build Next.js application (standalone mode)
 RUN npm run build
 

README.md

@@ -126,6 +126,8 @@ Open [http://localhost:3000](http://localhost:3000) in your browser.
 
 Replace the environment variables with your preferred AI provider configuration. See [Multi-Provider Support](#multi-provider-support) for available options.
 
+> **Corporate Networks:** If `embed.diagrams.net` is blocked, see [Self-Hosted Draw.io](./docs/self-hosted-drawio.md) for configuration options.
+
 ### Installation
 
 1. Clone the repository:

app/page.tsx

@@ -11,6 +11,9 @@ import {
 } from "@/components/ui/resizable"
 import { useDiagram } from "@/contexts/diagram-context"
 
+const drawioBaseUrl =
+    process.env.NEXT_PUBLIC_DRAWIO_BASE_URL || "https://embed.diagrams.net"
+
 export default function Home() {
     const { drawioRef, handleDiagramExport, onDrawioLoad } = useDiagram()
     const [isMobile, setIsMobile] = useState(false)
@@ -109,6 +112,7 @@ export default function Home() {
                                     ref={drawioRef}
                                     onExport={handleDiagramExport}
                                     onLoad={onDrawioLoad}
+                                    baseUrl={drawioBaseUrl}
                                     urlParameters={{
                                         ui: drawioUi,
                                         spin: true,

docs/self-hosted-drawio.md

@@ -0,0 +1,57 @@
+# Self-Hosted Draw.io Configuration
+
+In some corporate environments, `embed.diagrams.net` is blocked by network policies. This guide explains how to use a self-hosted draw.io instance with Next AI Draw.io.
+
+## Configuration
+
+Set the `NEXT_PUBLIC_DRAWIO_BASE_URL` environment variable to point to your self-hosted draw.io instance. This is a **build-time** configuration, meaning you need to rebuild the Docker image to change the URL.
+
+## Docker Build
+
+```bash
+# Build with custom draw.io URL
+docker build --build-arg NEXT_PUBLIC_DRAWIO_BASE_URL=http://your-drawio-server:8080 -t next-ai-draw-io .
+
+# Run the custom build
+docker run -d -p 3000:3000 --env-file .env next-ai-draw-io
+```
+
+## Docker Compose
+
+```yaml
+services:
+  drawio:
+    image: jgraph/drawio:latest
+    ports:
+      - "8080:8080"
+
+  next-ai-draw-io:
+    build:
+      context: .
+      args:
+        - NEXT_PUBLIC_DRAWIO_BASE_URL=http://drawio:8080
+    ports:
+      - "3000:3000"
+    env_file:
+      - .env
+```
+
+## Running Draw.io Locally
+
+You can run the official draw.io Docker image:
+
+```bash
+docker run -d -p 8080:8080 jgraph/drawio:latest
+```
+
+Then build Next AI Draw.io with:
+
+```bash
+docker build --build-arg NEXT_PUBLIC_DRAWIO_BASE_URL=http://localhost:8080 -t next-ai-draw-io .
+```
+
+## Notes
+
+- The default draw.io URL is `https://embed.diagrams.net`
+- Changes to `NEXT_PUBLIC_DRAWIO_BASE_URL` require rebuilding the Docker image
+- For local development, you can set this in `.env.local`

env.example

@@ -60,3 +60,7 @@ AI_MODEL=global.anthropic.claude-sonnet-4-5-20250929-v1:0
 
 # Access Control (Optional)
 # ACCESS_CODE_LIST=your-secret-code,another-code
+
+# Draw.io Configuration (Optional)
+# NEXT_PUBLIC_DRAWIO_BASE_URL=https://embed.diagrams.net  # Default: https://embed.diagrams.net
+# Use this to point to a self-hosted draw.io instance